Puerto Rico Blog Series: Climate Change and Hurricanes

Is climate change the cause of hurricanes? No warm, moist air over the ocean can take
credit for them. However climate change does play a role in the conditions necessary for the
formation of tropical cyclones (tropical depressions, tropical storms and hurricanes). While these
conditions exist on their own, they are not getting any better with climate change. Nevertheless
just like the topic of climate change, it is highly debated whether or not climate change has
played a role in the recent “Super Storms”.

On one side of the debate is the argument that climate change has nothing to do with
tropical cyclones. This argument is based on the fact that these natural disasters have been
around for hundreds of years. In their paper Donnelly and Woodruff indicate that climate change
is not to blame but instead storms are getting stronger due to natural cycles such as El Niño and
the West African monsoon. (Donnelly &amp; Woodruff, 2007) Similar arguments have been made for
this side of debate with the general consensus that there is no way climate change is affecting
hurricanes. However as Demaris Rosado- Alverado pointed out in her interview places such as
Puerto Rico take natural occurrences such as El Niño into consideration when discussing the
impact of climate change. While there is nothing they can do about El Niño, she indicates that
Puerto Rico has implemented sustainable programs to help combat climate change.

On the other side of the debate you have those that do not necessarily blame climate
change for the intensity of recent storms, but do agree that it has played a role in the storms we
see today. Hurricanes Irma and Maria took hundreds of lives and caused damage that will take
millions to fix. Both Irma and Maria turned into category 5 storms and were stronger than the
storms we have seen in the past couple of years. In the days following these storms world
leaders were quick to point to climate change as the culprit for these storms. A prime example
of this was the press conference given by António Guterres (UN Secretary-General) after the
storms. While he did indicate that he does not think any natural disaster should be linked to
climate change, he does note that the storms line up with scientist prediction models.

(Figure 1: Tropical Cyclone Metrics, IPCC AR5)

According to the Intergovernmental Panel on Climate Change (IPCC) climate change is unlikely the cause of the increase in the number of storms. Nevertheless their report does still support the claim that climate change has an effect on tropical cyclones. The IPCC indicates that “Evidence, however, is for a virtually certain increase in the…intensity of the strongest tropical cyclones since the 1970s in that [North Atlantic] region.”, but when you look at other regions the data is not as clear. (IPCC AR5) For example the data for the North Atlantic shows an interval range of change from –100% to +200% for the annual frequency of Category 4 and 5 storms. So while their metrics report does support the claim that climate change has an effect on hurricanes it is not too specific on how. Although on a global scale it is debatable if the intensity of these storms are increasing overall, one consensus can be drawn. That consensus is that future storms will have an increase in precipitation. This precipitation will cause huge flooding issues for coastal cities, as we have recently seen with Puerto Rico. Sea level rising, which can also be contributed to climate change, will mix with the heavy precipitation leading to deadly results.

Nevertheless there are some statements about climate change and hurricanes that can be declared. To start it can be said that climate change is not responsible for any one tropical cyclone (tropical depressions, tropical storms and hurricanes) in particular. It can also be stated that increase in tropical cyclone, wind-speed, and precipitation can be linked to warmer waters. Which in turn can be linked to the effects of climate change. Lastly it can be stated that sea level rise will play a large role in the impact these storms make. When it comes down to it, no climate change does not cause hurricanes, however climate change can be attributed to the increasing effects of the storms we face today.